Description
Dust obscured galaxies, such as those selected at submillimetre wavelengths, represent a population of strongly star-forming galaxies at $z \sim $1-4, which have been empirically claimed to have many properties expected for the progenitors of local spheroidal galaxies. It is unclear whether dusty galaxies are predominantly turbulent merger-driven systems like local ultra-luminous infrared galaxies (ULIRGs) with similarly high star-formation rates and dust masses, or if they closer resemble regular discs that are smoothly accreting gas from the intergalactic medium. Large unbiased samples of dust-obscured galaxies with reliably identified multi-wavelength counterparts were once lacking until the Atacama Large Millimeter/submillimeter Array (ALMA) provided sensitive 870-$\mu$m identifications of $\sim 1,000$ submillimetre galaxies (SMGs) in the UDS, COSMOS, and GOODS-S/ECDFS fields. To test these claims, I will present the initial findings from the KMOS+ALMA Observations of Submillimetre Sources (KAOSS) survey, a KMOS integral field spectroscopy study of an isotropic distribution of $\sim 350$ ALMA-identified galaxies which aims to derive precise spectroscopic redshifts to determine clustering and halo masses. KMOS observations of rest-frame optical emission enables 2-dimensional mapping of the spatially resolved ionised gas kinematics, which I will exploit to determine the trigger mechanisms of dust-obscured galaxies using the ratio between rotational velocity and intrinsic velocity dispersion, as it implies an amount of rotational support from in-situ star formation or turbulent motions from ongoing or recent mergers.
